President Gloria Macapagal Arroyo was 'fuming' and 'dismayed' and ordered an immediate, thorough investigation, Executive Secretary Eduardo Ermita said.

'It was definitely a work of the devil,' Mr Ermita told radio DZBB.

In one of the country's bloodiest bank robberies, seven bank employees, a depositor and a security guard were shot in the head in gangland-style executions on Friday, police said.

One employee was hospitalized in critical condition.

There has been speculation the victims may have been killed because they knew some of the robbers.

They were found sprawled on the floor of a branch of the Rizal Commercial Banking Corp. in Cabuyao town, in Laguna province south of Manila, after suspicious customers alerted authorities when the bank failed to open as scheduled at 9 am.

Laguna provincial police Chief Felipe Rojas said the provincial governor and a senator each offered 100,000 pesos while a private group - Friends of the Philippine National Police - gave 800,000 pesos to a reward kitty.

Mr Rojas said two security guards initially reported missing have been taken in for questioning. Both denied involvement and are not currently considered suspects, he said.

He said one explained he was not at the bank because he was on leave. The other gave inconsistent statements, he said, declining to give details.

He said both guards and all the victims were being tested to check if they had fired weapons. The guards are to undergo polygraph tests next week.

He said Philippine, US and Japanese currency worth about US$68,800 was found strewn on the floor, more than the initial estimate of US$10,000.

He said the robbers were believed to have fled with much more.

Rojas earlier said 'many' robbers were involved 'because this was a very complex operation.'

The robbers appeared to used a back door.

A vehicle owned by one of the bank employees was used by the robbers to escape. It was later recovered several kilometers away, he said. -- AP